DCT

2:26-cv-01844

Narwal Trading Hong Kong Co Ltd v. Shenzhen Shermon Technology Co Ltd

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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 2:26-cv-01844, W.D. Wash., 05/28/2026
  • Venue Allegations: Venue is alleged to be proper based on Defendant's agreement to jurisdiction in Seattle, Washington, as a condition of participating in Amazon's Patent Evaluation Express (APEX) program. Alternatively, venue is alleged to be proper because the defendant is not a U.S. resident.
  • Core Dispute: Plaintiff seeks a declaratory judgment that its robotic vacuum cleaner does not infringe Defendant's patent for a "dry-wet separation" cleaning brush and that the patent is invalid, following Defendant's use of an Amazon procedure that caused Plaintiff's product to be removed from sale.
  • Technical Context: The technology concerns the design of cleaning heads for robotic vacuums, specifically separating dry debris collection (sweeping/vacuuming) from wet cleaning (mopping) to improve performance in the competitive consumer robotics market.
  • Key Procedural History: This action was precipitated by Defendant's complaint against Plaintiff under Amazon's Patent Evaluation Express (APEX) program. This extra-judicial action resulted in the removal of Plaintiff's accused product listing from Amazon. The complaint alleges that the '975 patent is anticipated or rendered obvious by three prior art references.

Case Timeline

Date Event
2018-10-02 Publication of CN108606730A ('CN730') prior art reference
2020-03-26 '975 Patent Priority Date (JP 2020-055351)
2020-03-27 '975 Patent Application Filing Date
2022-11-22 '975 Patent Issue Date
2026-04-29 Defendant allegedly executed APEX Agreement to assert infringement
2026-04-30 Amazon sent APEX Notice to Plaintiff regarding the '975 Patent
2026-05-22 Amazon issued takedown notice, removing Plaintiff's product listing
2026-05-28 Complaint Filing Date

II. Technology and Patent(s)-in-Suit Analysis

U.S. Patent No. 11,503,975 - "Dry-Wet Separation Cleaning Floor Brush"

  • Patent Identification: U.S. Patent No. 11,503,975, "Dry-Wet Separation Cleaning Floor Brush," issued November 22, 2022 (the "'975 Patent").

The Invention Explained

  • Problem Addressed: The patent's background section describes drawbacks in existing robotic cleaners that combine sweeping, vacuuming, and mopping. These include the inability to automatically clean the mopping cloth and the tendency for dust and sewage to be stored together, which can lead to blockages and poor cleaning performance '975 Patent, col. 1:12-32
  • The Patented Solution: The invention is a cleaning floor brush assembly with a housing internally divided by a "partition plate" into two "disconnected" chambers '975 Patent, abstract A "stiff roller brush" for collecting dry debris resides in the first chamber, while a "soft roller brush" for mopping is in the second chamber '975 Patent, abstract '975 Patent, col. 1:50-62 This physical separation is intended to keep dry waste (dust) and wet waste (sewage) isolated from each other.
  • Technical Importance: This design purports to allow a single device to perform three cleaning functions-sweeping, vacuuming, and mopping-simultaneously while maintaining separate waste streams, which may improve overall cleaning efficacy and simplify maintenance '975 Patent, col. 2:50-54

Key Claims at a Glance

  • The complaint identifies independent claims 1, 9, and 16 as being at issue Compl. ¶28 Compl. ¶36
  • The complaint notes that Defendant's APEX submission asserted infringement of Claim 1 Compl. ¶35 Compl. Ex. B
  • Independent Claim 1 recites:
    • A dry-wet separation cleaning floor brush comprising a housing, a stiff roller brush and a soft roller brush;
    • wherein the housing is provided with a partition plate dividing the inner part of the housing into a first storage chamber and a second storage chamber which are disconnected to each other;
    • wherein the stiff roller brush is partially contained in the first storage chamber and is movably connected to the housing, and partially protrudes the housing;
    • and the soft roller brush is partially contained in the second storage chamber and is movably connected to the housing, and partially protrudes the housing;
    • wherein the first storage chamber is provided with a vacuum cavity, a dust collection cavity, and a dust passage connecting them.
  • The complaint reserves the right to amend with additional claims or defenses as the dispute evolves Compl. ¶43

III. The Accused Instrumentality

Product Identification

  • The complaint identifies the Accused Product as a "Narwal-branded robot vacuum" sold on Amazon under ASIN B0F6CWKBTN Compl. ¶13

Functionality and Market Context

  • The product is described as part of Narwal's line of "high-end, artificial intelligence-powered robotic vacuums and mops and base stations" Compl. ¶¶12-13
  • The complaint's primary technical allegation is a negative one: that the Accused Product "does not, at a minimum, meet the claim limitation reciting 'a partition plate [provided within a housing of the product] dividing the inner part of the housing into a first storage chamber and a second storage chamber which are disconnected to each other'" Compl. ¶22
  • Plaintiff alleges that the Amazon marketplace is a "primary sales channel" and that the product's removal has caused "immediate and irreparable harm... including loss of sales, market share, and associated goodwill" Compl. ¶18 The complaint includes a printout from the Amazon listing page that was removed. This visual, referenced as Exhibit C, shows the Accused Product and its branding Compl. ¶13

IV. Analysis of Infringement Allegations

As this is a complaint for declaratory judgment of non-infringement, the allegations are framed as denials of infringement. The complaint focuses its non-infringement argument on a single, core limitation common to the independent claims.

'975 Patent Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
A dry-wet separation cleaning floor brush comprising a housing, a stiff roller brush and a soft roller brush... The Accused Product is identified as a "robot vacuum" Compl. ¶13 The complaint does not provide specific details on its internal components, such as the presence of a stiff or soft roller brush. ¶13 col. 1:47-49
...wherein the housing is provided with a partition plate dividing the inner part of the housing into a first storage chamber and a second storage chamber which are disconnected to each other... Plaintiff explicitly alleges that the Accused Product does not meet this limitation. The complaint contends the product lacks a partition plate that divides the housing into two disconnected storage chambers as recited in the claim Compl. ¶22 ¶22; ¶30 col. 1:50-55
...wherein the stiff roller brush is partially contained in the first storage chamber and is movably connected to the housing, and the stiff roller brush partially protrudes the housing; and the soft roller brush is partially contained in the second storage chamber and is movably connected to the housing, and the soft roller brush partially protrudes the housing... The complaint does not provide specific details regarding the placement or function of any roller brushes within the Accused Product. - col. 1:55-62
...wherein the first storage chamber is further provided with a dust collection cavity and a dust passage through which the vacuum cavity is connected with the dust collection cavity... The complaint does not provide specific details regarding the dust collection or vacuum mechanism of the Accused Product. - col. 2:21-25
  • Identified Points of Contention:
    • Scope Questions: The central infringement dispute presented in the complaint revolves around the construction of "partition plate" and "disconnected to each other." The case raises the question of what degree of structural and functional separation is required to satisfy this limitation.
    • Technical Questions: A key factual question is the actual internal construction of the Accused Product. The complaint does not provide diagrams or technical descriptions, so determining whether any component of the device could be construed as a "partition plate" creating "disconnected" chambers will depend on evidence produced during discovery.

V. Key Claim Terms for Construction

  • The Term: "partition plate"

    • Context and Importance: This term is the lynchpin of Plaintiff's non-infringement argument Compl. ¶22 Compl. ¶30 Its construction will determine the structural requirements for infringement. Practitioners may focus on this term because its presence or absence appears to be the primary point of contention regarding infringement.
    • Intrinsic Evidence for Interpretation:
      • Evidence for a Broader Interpretation: The claim language itself is functional, describing the plate as "dividing the inner part of the housing" '975 Patent, col. 4:1-3 A patentee might argue that any internal wall that serves to separate the housing into two sections meets this definition.
      • Evidence for a Narrower Interpretation: The specification consistently links the partition plate (11) to the specific purpose of separating the "first storage chamber (12)" for vacuuming from the "second storage chamber (13)" for mopping, which are described as "disconnected" '975 Patent, col. 1:50-55 An accused infringer may argue this requires a distinct, dedicated component that achieves a high degree of separation, as depicted in Figure 1.

  • The Term: "disconnected to each other"

    • Context and Importance: This phrase modifies the relationship between the two chambers created by the partition plate. Its interpretation is critical to defining the required level of separation and, therefore, what constitutes an infringing device.
    • Intrinsic Evidence for Interpretation:
      • Evidence for a Broader Interpretation (for Patentee): A patentee could argue "disconnected" means functionally separate in normal operation (i.e., dry debris is not intended to mix with wet sewage), not necessarily hermetically sealed. The patent's stated goal is to avoid the problems of mixing dust and sewage, suggesting a functional rather than absolute separation '975 Patent, col. 1:29-32
      • Evidence for a Narrower Interpretation (for Accused Infringer): Plaintiff may argue that "disconnected" implies a complete lack of fluid or particulate communication between the chambers. If the Accused Product's design allows for any potential commingling of dry and wet waste, it could be argued that its chambers are not "disconnected."

VI. Other Allegations

  • Indirect Infringement: The prayer for relief asks for a declaration of non-infringement "directly or indirectly" Compl. p. 9, Prayer B However, the complaint does not plead any specific facts related to inducement or contributory infringement, such as allegations regarding user manuals or intent.
  • Willful Infringement: This section is not applicable, as willfulness has not been alleged by the patentee in this declaratory judgment action initiated by the accused infringer. The complaint does seek a declaration that the case is exceptional for the purpose of attorneys' fees Compl. p. 9, Prayer C

VII. Analyst's Conclusion: Key Questions for the Case

This case presents a two-front dispute common in patent litigation, focusing on both non-infringement and invalidity. The central questions for the court appear to be:

  • A question of claim construction and infringement: Will the claim terms "partition plate" and "disconnected to each other" be construed broadly enough to read on the internal architecture of the Accused Product? The resolution will depend first on the court's interpretation of the patent's language and then on the factual evidence of the product's design.

  • A question of validity: Is the '975 Patent valid over the prior art? The complaint asserts with some specificity that the CN730, US020, and WO795 references disclose the claimed invention Compl. ¶¶37-39, framing a significant challenge that the patentee must defend against, independent of the infringement analysis.

  • A procedural question with commercial implications: The dispute's origin in the Amazon APEX program highlights the growing role of extra-judicial enforcement mechanisms. The commercial pressure from this "takedown" action likely motivated the filing of this declaratory judgment suit, and the outcome may influence how parties approach similar disputes on e-commerce platforms in the future.

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